One of the goals of plant genetic engineering is to produce plants with agronomically desirable characteristics or traits. The proper expression of a desirable transgene in a transgenic plant is one way to achieve this goal. Promoters are non-coding polynucleotide molecules which play an integral role in the overall expression of genes in living cells. Isolated promoters that function in plants are useful for modifying plant phenotypes through the methods of genetic engineering.
Many constitutive promoters are available and are useful for providing good overall gene expression. For example, constitutive promoters such as P-FMV, the promoter from the 35S transcript of the Figwort mosaic virus, (U.S. Pat. No. 6,051,753); P-CaMV 35S, the promoter from the 35S RNA transcript of the Cauliflower mosaic virus, (U.S. Pat. No. 5,530,196); P-Rice Actin 1, the promoter from the actin 1 gene of Oryza sativa, (U.S. Pat. No. 5,641,876); and P—NOS, the promoter from the nopaline synthase gene of Agrobacterium tumefaciens are known to provide some level of gene expression in most or all of the tissues of a plant during most or all of the plant's lifespan. Alternately, many promoters are available with more specific expression patterns such as tissue specificity, temporal specificity, or developmental specificity. These promoters are useful for the targeted expression of a transgene in plants.
Optimal expression of a transgene is useful for producing plants with agronomically desirable characteristics or traits. Such optimal expression often requires a promoter having a specific expression pattern which may not be readily available in known promoters. One example of such a specific expression pattern is a high level of transgene expression in both vegetative and reproductive tissues. The present invention solves this problem by producing novel chimeric promoters containing elements from known promoters. These novel chimeric promoters can then be tested in plants to determine whether the desired expression pattern is indeed achieved.